There are amount-of-movement calculation methods of the related art in which an amount of movement of an object is calculated based on moving-image data acquired by capturing images of the object. For example, Japanese Laid-open Patent Publication No. 2009-130537 discloses a method of calculating an amount of movement of an object. In the disclosed method, a plurality of feature points of the object are extracted from a frame of moving-image data. Then, a destination of each of the plurality of feature points after movement in the next frame is identified, and an amount of displacement of each of the plurality of feature points is determined. The amount of movement of the object is obtained by calculating the average of the amounts of displacements of all the feature points.
In the method disclosed in Japanese Laid-open Patent Publication No. 2009-130537, a region that correlates well with a feature point in a current frame is acquired from the next frame, and a position of the center of gravity of the acquired region is identified as the destination of the feature point after movement. Thus, an amount of movement is calculated even if the next frame is a blurred image as a result of the movement of the object. As a related-art technical document, Japanese Laid-open Patent Publication No. 2009-130537 is disclosed.